title: Dual roles of the transcription factor grainyhead-like 2 (GRHL2) in breast cancer.
abstract: Using a retrovirus-mediated cDNA expression cloning approach, we identified the grainyhead-like 2 (GRHL2) transcription factor as novel protooncogene. Overexpression of GRHL2 in NIH3T3 cells induced striking morphological changes, an increase in cell proliferation, anchorage-independent growth, and tumor growth in vivo. By combining a microarray analysis and a phylogenetic footprinting analysis with various biochemical assays, we identified the epidermal growth factor receptor family member Erbb3 as a novel GRHL2 target gene. In breast cancer cell lines, shRNA-mediated knockdown of GRHL2 expression or functional inactivation of GRHL2 using dominant negative GRHL2 proteins induces down-regulation of ERBB3 gene expression, a striking reduction in cell proliferation, and morphological and phenotypical alterations characteristic of an epithelial-to-mesenchymal transition (EMT), thus implying contradictory roles of GRHL2 in breast carcinogenesis. Interestingly, we could further demonstrate that expression of GRHL2 is directly suppressed by the transcription factor zinc finger enhancer-binding protein 1 (ZEB1), which in turn is a direct target for repression by GRHL2, suggesting that the EMT transcription factors GRHL2 and ZEB1 form a double negative regulatory feedback loop in breast cancer cells. Finally, a comprehensive immunohistochemical analysis of GRHL2 expression in primary breast cancers showed loss of GRHL2 expression at the invasive front of primary tumors. A pathophysiological relevance of GRHL2 in breast cancer metastasis is further demonstrated by our finding of a statistically significant association between loss of GRHL2 expression in primary breast cancers and lymph node metastasis. We thus demonstrate a crucial role of GRHL2 in breast carcinogenesis.
authors.affiliation: Department of Tumor Biology, Leibniz-Institute for Experimental Virology, Virus Genomics, Hamburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Werner
authors.forename: Sabrina
authors.initials: S
authors.lastname: Frey
authors.forename: Sabine
authors.initials: S
authors.lastname: Riethdorf
authors.forename: Christian
authors.initials: C
authors.lastname: Schulze
authors.forename: Malik
authors.initials: M
authors.lastname: Alawi
authors.forename: Lea
authors.initials: L
authors.lastname: Kling
authors.forename: Vida
authors.initials: V
authors.lastname: Vafaizadeh
authors.forename: Guido
authors.initials: G
authors.lastname: Sauter
authors.forename: Luigi
authors.initials: L
authors.lastname: Terracciano
authors.forename: Udo
authors.initials: U
authors.lastname: Schumacher
authors.forename: Klaus
authors.initials: K
authors.lastname: Pantel
authors.forename: Volker
authors.initials: V
authors.lastname: Assmann
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D008207:Lymphatic Metastasis; D015674:Mammary Neoplasms, Animal / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D041681:NIH 3T3 Cells; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000071799:Zinc Finger E-box-Binding Homeobox 1
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D051741:Kruppel-Like Transcription Factors; D018719:Erb-b2 Receptor Tyrosine Kinases; D014157:Transcription Factors; D000071799:Zinc Finger E-box-Binding Homeobox 1; C470830:GRHL2 protein, human; C486307:ZEB1 protein, human; C519422:ZEB1 protein, mouse; C552738:grainy head-like 2 protein, mouse; C508053:ERBB2 protein, human; C524056:Erbb2 protein, mouse
keywords: Breast Cancer; Epithelial Cell; Epithelial-to-mesenchymal Transition; Metastasis; Oncogene